Insulating compound.



UNITED STATES PATENT OFFICE.

GEORGE A. JACOBS, OF CLEVELAND, OHIO, ASSIGNOR TO THE SHERWIN-WILLIAMS COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

INSULATING COMPOUND.

No Drawing.

7 '0 all whom it may coricern Be it known that I, Gnoncn A. JAooBs, a

citizen of the United States, resident of Cleveland, county of Cuyahoga, and State of Ohio, have invented :a new and useful Improvement in Insulating Compounds, of which the following is a specification, the principle of the invention being herein explained and the best mode in which I have contemplated applying that principle, so as to distinguish it from other inventions,

The subject matter of this my present invention is a new composition'of matter that is designed specifically for use as an insulating compound for impregnating electric'al coils, such as are used in the various types of electrical machinery and particularly in transformers. The requirements which such a compound must meet; are, as

is well known, quite severe. Primarily, of

course, the compound -must haye high in; sulating. qualities, otherwise it is useless on electrical apparatus. To this must be joined an ability to withstand continued heat without decomposing or otherwise changing, while the coil insulated thereby must berendered proof against the effects of moisture, as also, in case the coils are designed for use in transformers or the like, against the classof oils ordinarily employed in cooling transformer apparatus. It is to provide a compound that will successfully meet "these and' 'rela t e d requirements that I have devised the composition of matter, the ingredients and method -of preparation of which will now be described and particu-.

larly set forth in the claims. s

The following description set forth in detail one approved/mode of carrying out my invention, suchdisclosed mode, however, constituting but one of various ways in which the principle of the invention may be used.

The manner in which I prepare my new Specification of Letters Patent.

Application filed April 8. 1%? Serial No. 866,880.

Patented July 8, 1913.

For the gum, which is thus seen to form ineffect the base of the compound I prefer to employ that "variety of copal known to the trade as Manila gum. A- quantity of such gum is placed in a varnishmakers kettle and fusedto five hundred and fifty to five hundred and seventy-five degrees, Fahrenheit for from ten to fifteen minutes by which time the lighternatural oils will have been driven off. Thereupon the proper amount of linseed oil is added, and the re- "sult-ant mixture is maintained at a temperature of approximately five hundred and forty degrees for from two and one-half to The lowering of the temperature just pre-' vious to this second stage of the operation is conveniently made-incidental to the addition of the linseed oil. During such second-or' latter stage in the foregoing course of preparation ofthe varnish, I also prefer to-add a small quantity of selected gilsonite or asphaltum gum. Also a small percentage of drying oil is desirably intermingled, therewith at the conclusion of such operation, the use otwhich in the subsequent application of the compound will be obvious.

The preferred proportions in which-I employthe'foregoing ingredients are approximately as follows: Of the gum thirty parts; of the oil three parts; and of the asphaltiim, when used, one part; while of the drier ordinarily a quantity equal to from two to three' per cent. of the amount of compound which it is being added will be found sufiicient. A precise formula that I have found to work out with eminent success is madeup of from one hundred and fifty to one hundred and sixty pounds of the Manila or semi-fossil gum; seventeen and seven-tenths pounds of inseed oil; and four and one-half to five pounds of the selected gilsonite of asphaltum gum; five pounds of drying oil. It will, of course, be understood that the exact riod for which the several steps involved in the preparation of the Varnish should continue may require to be curtailed or exet-ended dependin upon various conditions 105 periods in the manufacture of this as in other compounds.

As has been indicated the compound herein described is designed especially for use 5 in the impregnating process of treating electricel coils, particularly in the so called.

vacuumdrying and impregnating process. It 18 especially adapted for impregnating transformer and all other coils operating in 10 a cooling bath of minerel oils. Not only is it possessed oflhe necessary insulating qualities, and proof. against both oil and moisture but it is chemicelly inert and Will not attack the copper or injure the cotton incasing the same inany way even when warmed, as under operative conditions.

The compound produced sis-above, aside from being chemically inactive, and itself mmieeted, et such operative temperatures even where thesereach a maximum of two hundred degrees Fahrenheit, it nevertheless F becomes quite fluid "at :1 temperature of two hundred and seventy five degrees or slightly thereabove; It will thus be seen to have av very good penetration, enabling it to he forced thoroughly through the coils, therehy cementing the latter into solid oil and moisture proof masses 'which are not only impervious to any 1n]ur1ous substances that might harm the insulation, but which are.

my inventionmey be employed retard of 'tions by Weight of approxim iw messes so strong mechanically that may cnnotbe rendered practically from extreme over-lee Other modes of a-pi lyi g the 3 the one explained, chs'iig regards the process here" vided the step or steps" of the following claims r of such stated step or steps l) I therefore particularly en; tinct-ly claim as my invention 1. An insulating compou Manila gum and linseed oil if Signed bynie this 5th day of April, 1907. 55

GEORGE A. JACOBS.

Austen by D. T. DAVIES,

Jno. T. OBERLiN.

Oeplas of this patent may be obtained for five cents each, by addressing the, Commissioner of-Patents.

Washington, D. C. 

